In recent years, with the miniaturization of semiconductor devices, a finer etching process called a chemical oxide removal (COR) process has been used instead of conventional etching techniques such as dry etching or wet etching.
The COR process is a process of supplying a hydrogen fluoride (HF) gas and an ammonia (NH3) gas as process gases onto, for example, a silicon oxide (SiO2) film formed on a surface of a semiconductor wafer (hereinafter, referred to as a “wafer”) as a substrate under vacuum and allowing the process gases to react with the silicon oxide film so as to produce a reaction product (for example, Patent Document 1). In the COR process, in order to maintain a temperature of the wafer at a desired temperature, the wafer is subjected to a process in a state where the wafer is placed on a placing table configured to adjust the temperature of the wafer.
In addition, the product produced on the surface of the wafer by the COR process is sublimated by heating performed in a subsequent process so that the silicon oxide film is removed from the surface of the wafer.